A fire broke out on campus at the University of California, Riverside (UCR) and prompted immediate evacuation and disbursement of the fire investigator and Hazardous Materials Team to investigate the situation. The fire was reported at 2:20 p.m on Jan. 16, 2024 in Physics building 1159 on the northeast side of campus near Winston Chung Hall. While the cause of the fire has not been determined as of publication, investigations are currently underway.
The wing of the Physics building where the fire occurred is known as the annex and is home to the Positron Laboratory which is located in room 1159 according to a paper posted on an exterior entrance. The building was promptly evacuated by the UCR Building Emergency Staff and no civilian injuries were reported.
The Positron Laboratory, according to their website, focuses on the Positronium (Ps) Physics, a physics based on the antiparticle of electrons, “with the ultimate goal of fabricating a Bose-Einstein Condensation of Ps,” a unique quantum state of matter.
According to UCR’s Director of Emergency Management Andrew Flores, “Like most labs on campus, hazardous materials are present in some form and the first responders are always concerned with necessary precautions, so once the initial fire was extinguished, they secured the building and called in the HazMat team who have expertise.”

Found on the emergency sheet posted on the exterior of the building, the National Fire Protection Association 704 diamond identifies the hazards of materials for emergency response in the lab. The assessment designates the lab as a level three health hazard, meaning it has the potential to “cause serious or permanent injury.” In terms of flammability, it is ranked as a level four, meaning it “will rapidly or completely vaporize at atmospheric pressure and normal ambient temperatures … and burn easily.” With a level three designation for instability, it is “readily capable of detonation or explosive decomposition at normal temperatures and pressures.” The lab also has a special hazard warning for containing simple asphyxiant gas.
Other hazards and special concerns listed for the lab include a strong magnetic field, high voltage, radioactive materials or radiation producing machine and lasers. The lab was last certified on Oct. 11, 2023.
It is still unclear as to whether or not any of the chemicals in the lab caught on fire and what items were inside of the lab.
Campus fire marshals, Environmental Health & Safety Personnel, Office of Emergency Management, UC Police Department (UCPD) and the City Fire Department responded to the scene of the fire and secured the building.
Lieutenant Jason Day of UCPD shared, “Dispatch received the initial set of alarms around 2:15 p.m. and immediately notified the Riverside Fire Department (RFD), as well as dispatching our own officers. Our officers created a perimeter around the building to allow RFD to work, and assisted with the evacuations of staff, faculty and students.”
The fire was contained within 30 minutes of first responders arriving and the fire investigator and Hazardous Materials Team were sent to the scene of the fire to conduct a preliminary investigation.
Director Flores reports that the HazMat team was unable to come to conclusions, leading to the building to not be secured until the following morning.
The Campus Fire Marshal Scott Jackson shared that the State Fire Marshall will be coming to UCR on Tuesday, Jan. 21 to conduct a follow-up assessment and identify the source of the fire. As of the nineteenth of January , the cause of the fire is still unknown, and the annex and lab will be closed to civilians until it is determined.

Reports have been made stating that there is fire damage to the interior of the annex but the extent of the damage will not be known until UCR personnel can assess the scene.
The rest of the Physics building was reopened around 5 p.m. and instruction continued as normal.
Kaleb Teklebrhan, a second-year chemical engineering major, was in the Physics 2000s building, a neighboring room, when the fire alarm was set off. He reported that he initially was unable to see or hear anything during the evacuation, but the smoke became visible coming from the building after walking down the hill towards the annex.
Three UCR Highlander Alerts were sent out to students and faculty in order to update them on the situation. The first was sent at 2:58 p.m., more than 30 minutes after the fire was reported to UCPD and informed the campus community that there was a fire incident in Physics and to remain out of the area. The second update came at 3:49 p.m., informing people that the situation was contained, but traffic is still impacted and to remain out of the area. The final report at 6:48 p.m. announced that the incident was resolved and that streets have been reopened.